The present disclosure generally relates to a hybrid vehicle drive train and, more particularly, to a method of adjusting the torque output of the drive train to match a target power profile.
Over the past few years, there has been a growing concern over global climate change due to an increase in carbon dioxide levels as well as oil supply shortages. As a result, automobile manufactures and consumers are developing a greater interest in motor vehicles having lower emissions and increased fuel efficiency. One viable option is a hybrid electric vehicle which allows the vehicle to be driven by electric motors, combustion engine, or a combination thereof.
Transmissions in hybrid drive trains serve a number of functions by transmitting and manipulating torque in order to provide torque to an output member. The driver, through actuation of the accelerator, brake pedal, and auxiliary braking selectors, commands the engine and/or electric motor to provide a desired power to the vehicle drive train. The transmission is expected to accurately implement the driver's command. As the transmission changes the gear ratio, the driver's intent is not always achieved. Gear shifts within transmissions often result in disturbances in the drive train power output profile. The disturbances manifest as vibrations in the vehicle which are felt by the driver and passengers. Such disturbances can cause discomfort to the driver and passengers or otherwise create an undesirable driving experience.
Hybrid vehicle drive trains provide additional options for tailoring power output profiles based on a user's particular needs. For example, the power profile can be tailored to provide many different functions such as optimizing fuel economy, maximizing acceleration, reducing or eliminating vibrations from gear shifts, or otherwise smoothing the drive train power profile for driver and passenger comfort. However, problems exist with transforming a drive train power input to a desired drive train power.
Thus, there is a need for improvement in this field.